A New Method of Synthesis of Aspartic Acid/Lactic Acid Copolymers Under Microwave Field

Aspartic acid/lactic acid copolymers were synthesized under microwave radiation, without a catalyst, by bulk and solution method. The reaction was carried out also in the presence of phosphoric acid as the catalyst and with the use of a conventional heating. Furthermore, partial degradation of the copolymers by hydrolysis in a physiological NaCl solution and in the Lactated Ringer's solution was investigated. The structure of the products was characterized by Fourier-transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H NMR). Thermalproperties of the aspartic acid/lactic acid copolymers were determined by thermogravimetry (TG) and differential scanning calorimetry (DSC), while their molecular weight was measured by gel permeation chromatography (GPC).